Tractor, tractor unit, and recording device

ABSTRACT

Plural tractors that convey recording media in a recording device can be disposed in close proximity to each other. A tractor module  101  that conveys continuous paper  2  has a gear  117  that receives drive power from the printer unit 10 side of the printer 1, tractors  120, 130  that convey the continuous paper  2  in a specific direction by rotation of the gear  117,  and a frame  111  that guides the continuous paper  2  supplied from an external source to the tractors  120, 130.

BACKGROUND

1. Technical Field

The present invention relates to a tractor that conveys a recording medium, a tractor unit having the tractor, and a recording device having the tractor unit.

2. Related Art

Recording devices that have a tractor to convey recording media, and record while conveying recording media with the tractor, are known from the literature. Some such recording devices have plural tractors. See, for example, Japanese Unexamined Patent Appl. Pub. JP-A-S64-8071. The recording device described in JP-A-S64-8071 enables changing which of the plural tractors is used. For example, this recording device can change the recording medium that is used by selecting which tractor is used. As a result, the desired recording medium can be selected for use from among plural recording media without removing the recording medium from the tractor.

As described in JP-A-S64-8071, however, recording devices having plural tractors generally have the tractors disposed to convey the recording media to the recording head from different directions. The tractors therefore use separate conveyance paths in this configuration. The tractors are also disposed to separate locations. Contact between the recording media conveyed by the different tractors can therefore be avoided. Depending upon the specifications of the recording head, however, the recording media cannot be fed to the recording head from different directions. Due to the design limitations of the recording device, disposing the plural tractors to greatly different positions may also not be possible. Recording devices therefore typically do not have plural tractors because of the possibility of collisions between the recording media.

SUMMARY

A recording device according to the present invention enables disposing plural recording media conveyance tractors in close proximity to each other.

One aspect of the invention is a tractor that conveys a recording medium, and has: a gear that receives drive power from the recording device side; a conveyance unit that conveys the recording medium in a specific direction by rotation of the gear; and a frame that guides the recording medium supplied from an external source to the conveyance unit.

This aspect of the invention guides the recording medium conveyed by the tractor with the frame. As a result, contact between recording media conveyed by plural tractors can be avoided. A configuration having plural tractors disposed in close proximity to each other can therefore be achieved.

Preferably, the frame of the tractor has a supply-side guide that passes the recording medium.

This aspect of the invention can restrict movement of the recording medium by passing the recording medium through a slot in the frame. As a result, contact between recording media conveyed by different tractors can be avoided when plural tractors are disposed close together. A configuration having plural tractors disposed in close proximity to each other can therefore be achieved.

In a tractor according to another aspect of the invention, the frame has a discharge-side guide that passes the recording medium conveyed by the conveyance unit.

This aspect of the invention guides the recording medium conveyed by each tractor with the frame of the tractor. As a result, contact between recording media conveyed by different tractors can be avoided when plural tractors are disposed close together. A configuration that provides the recording device with plural tractors, and enables each of the plural tractors to convey recording media in the same direction, can therefore be achieved.

In a tractor according to another aspect of the invention, the discharge-side guide has an opening on the discharge side from which the recording medium is discharged, and an opening on the conveyance unit side, and the width of the opening on the conveyance unit side is narrower than the width of the opening on the discharge side.

This configuration can firmly restrict movement of the recording medium conveyed by the tractor to avoid inference with recording media conveyance. As a result, contact between recording media conveyed by the plural tractors can be more reliably avoided. A configuration that provides the recording device with plural tractors, and enables each of the plural tractors to convey recording media in the same direction, can therefore be achieved.

Another aspect of the invention is a tractor unit that has a plurality of tractors, each of which conveys a recording medium, and has a gear that receives drive power from the recording device side, a conveyance unit that conveys the recording medium in a specific direction by rotation of the gear, and a frame that guides the recording medium supplied from an external source to the conveyance unit; and a base that removably holds the plural tractors, and has at least one transfer gear that receives and transfers drive power from a power transfer unit disposed on the recording device side to the gears of the plural tractors.

This aspect of the invention provides plural tractors in the tractor unit, and guides the recording medium conveyed by each tractor with the frame of the tractor. As a result, contact between the recording media conveyed by the plural tractors can be avoided. A recording device having plural tractors disposed close together can therefore be achieved.

In a tractor unit according to another aspect of the invention, the plural tractors are disposed in plural stages vertically, and configured so that the recording medium conveyed by the tractor located above another tractor does not contact the recording medium conveyed by the lower tractor; and the tractor unit has a selection mechanism that changes the tractor that receives drive power from the transfer gear.

This configuration disposes plural tractors vertically, and enables changing the tractor that conveys the recording medium to a part of the recording device that receives the recording medium in the group of plural tractors. Contact between the recording media conveyed by the plural tractors can also be avoided. Recording media can therefore be conveyed consistently even when plural tractors are disposed close together.

In a tractor unit according to another aspect of the invention, the selection mechanism has a moving mechanism that moves the tractors held in plural stages vertically; and the transfer gear transfers drive power to the tractor at a specific height in the group of plural tractors.

This aspect of the invention enables easily changing the tractor that conveys the recording medium to the part of the recording device that receives the recording medium in the group of plural tractors. In addition, the tractor set to a specific height always conveys the recording medium to the part of the recording device that receives the recording medium. A special configuration is therefore not needed in the part of the recording device that receives the recording medium, and the recording media can be conveyed stably.

In a tractor unit according to another aspect of the invention, each tractor lifts and conveys the recording medium from below; and the lifting position at which a tractor located above another tractor lifts the recording medium is on the side separated more from the recording device than the lifting position of the tractor located therebelow.

This aspect of the invention more reliably avoids contact between the recording media conveyed by the plural tractors disposed one above the other. The recording media can therefore be conveyed stably.

In a tractor unit according to another aspect of the invention, the frame is disposed to the tractor extending to the side away from the recording device, and guides the recording medium lifted from below so that the recording medium does not contact the recording medium conveyed by another tractor.

This aspect of the invention can keep the recording media conveyed by the plural tractors disposed one above the other separated. A configuration that avoids contact between the recording media can therefore be easily achieved.

In a tractor unit according to another aspect of the invention, the frame of the tractor located higher in the group of plural tractors extends to a position separated farther from the recording device than the frame of the tractors located therebelow.

This aspect of the invention can keep the recording media conveyed by the plural tractors disposed one above the other separated. A configuration that avoids contact between the recording media can therefore be more easily achieved.

In a tractor unit according to another aspect of the invention, the plural tractors are positioned along a slope to the vertical so that the distance from the recording device increases as the height of the position increases.

This configuration can keep the recording media conveyed by the plural tractors disposed one above the other separated even when the plural tractors disposed one above the other have the same shape. A configuration that avoids contact between the recording media can therefore be more easily achieved. Limitations on the shape and size of the tractors can therefore be alleviated.

Another aspect of the invention is a recording device that has a tractor unit having a plurality of tractors that convey recording media, and a base that removably holds the plural tractors, each tractor of the tractor unit having a gear that receives drive power from the recording device side, a conveyance unit that conveys the recording medium in a specific direction by rotation of the gear, and a frame that guides the recording medium supplied from an external source to the conveyance unit, and the base of the tractor unit having at least one transfer gear that receives and transfers drive power from a power transfer unit disposed on the recording device side to the gears of the plural tractors.

This aspect of the invention provides plural tractors in the tractor unit, and guides the recording medium conveyed by each tractor with the frame of the tractor. As a result, contact between the recording media conveyed by the plural tractors can be avoided. A recording device having plural tractors disposed close together can therefore be achieved.

Preferably, the plural tractors of the recording device are disposed in plural stages vertically, and configured so that the recording medium conveyed by the tractor located above another tractor does not contact the recording medium conveyed by the lower tractor; and the tractor unit has a selection mechanism that changes the tractor that receives drive power from the transfer gear.

This configuration disposes plural tractors vertically to the recording device, and enables changing the tractor that conveys the recording medium to the recording device in the group of plural tractors. Contact between the recording media conveyed by the plural tractors can also be avoided. Recording media can therefore be conveyed consistently even when plural tractors are disposed close together.

Effect if the invention

The invention enables avoiding contact between the recording media conveyed by plural tractors. As a result, a recording device having plural tractors disposed close to each other can be achieved.

Other objects and attainments together with a fuller understanding of the invention will become apparent and appreciated by referring to the following description and claims taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an oblique view showing the general configuration of a printer according to a first embodiment of the invention.

FIG. 2 is an oblique view of the printer when the tractor unit is not installed.

FIG. 3 is a section view showing main parts of the printer when the tractor unit is not installed.

FIG. 4 is a function block diagram showing the control configuration of the printer.

FIG. 5 is an oblique view from the back of the printer when the tractor unit is installed.

FIG. 6 is an oblique view showing the configuration of the tractor module.

FIG. 7 is an oblique view showing the internal configuration of the tractor unit in detail.

FIG. 8 is a section view showing main parts of the printer when the tractor unit is installed.

FIGS. 9A, 9B, and 9C describes the mechanism that moves the tractor drive gear in detail.

FIGS. 10A and 10B is an oblique view of the tractor module according to a second embodiment of the invention.

FIG. 11 is an oblique view of the tractor module according to a third embodiment of the invention.

FIG. 12 is an oblique view of the tractor module according to a third embodiment of the invention.

FIG. 13 is a section view of the tractor module according to a third embodiment of the invention.

FIG. 14 is an oblique view of the tractor module according to a fourth embodiment of the invention.

FIG. 15 is a section view of the tractor module according to a fourth embodiment of the invention.

FIG. 16 is an oblique view of a printer according to a fifth embodiment of the invention.

FIG. 17 is an oblique view from the back of the printer when the tractor unit is installed.

FIG. 18 is an oblique view showing the configuration of the tractor unit in detail.

FIG. 19 is an enlarged oblique view showing the configuration of the tractor unit in detail.

FIG. 20 is an oblique view of the tractor module.

FIG. 21 is a section view showing the configuration of the tractor unit.

FIG. 22 is a section view of a tractor unit according to a sixth embodiment of the invention.

FIG. 23 is a section view of a tractor unit according to a seventh embodiment of the invention.

DESCRIPTION OF EMBODIMENTS Embodiment 1

A first embodiment of the present invention is described below with reference to the accompanying figures.

FIG. 1 is an oblique view from the front of a printer 1 according to a first embodiment of a recording device according to the invention.

This printer 1 is an inkjet printer that forms text and images by ejecting four colors of ink, C (cyan), M (magenta), Y (yellow), and K (black), onto the recording surface of a recording medium. This printer 1 uses continuous paper 2 having sprocket holes 2 a formed along both edges of the paper width as the recording medium. The printer 1 takes the continuous paper 2 in from the back (rear) side of the printer 1, records (prints) on the continuous paper 2, and discharges the continuous paper 2 after recording from a paper exit 11 formed in the front of the printer 1.

The printer 1 includes a printer unit 10 (recording unit) that records on the recording medium, and a tractor unit 5 that is removably installed to the back of the printer unit 10.

The printer unit 10 has a box-like case 12 housing the recording mechanism that records text and images. The paper exit 11 is open in the front of the case 12. A paper guide 13 is disposed to the paper exit 11 projecting from the front of the case 12. The paper guide 13 communicates with the conveyance path through which the continuous paper 2 is conveyed inside the case 12. The continuous paper 2 rides over the paper guide 13 and is discharged through the paper exit 11 from the printer unit 10.

Two doors 14 are disposed to the front of the printer unit 10. Space for holding four ink cartridges, that is, an ink cartridge storing cyan (C) ink, an ink cartridge storing magenta (M) ink, an ink cartridge storing yellow (Y) ink, and an ink cartridge storing black (K) ink, is provided inside the doors 14. Ink is supplied to the recording head 31 described below from the four ink cartridges held in this space.

A power switch 15 for turning the printer 1 power on and off is also provided in the front of the printer unit 10. An operating panel 16 with switches for controlling settings related to printer 1 operation, and indicators for displaying printer 1 operating states, is also provided in the front of the printer unit 10.

The tractor unit 5 has a plurality of tractor modules (tractors), each of which conveys continuous paper 2. The number of tractors in the tractor unit 5 is not specifically limited. This embodiment describes an exemplary configuration having three tractor modules (tractors) 101, 102, 103 (see FIG. 5) in the tractor unit 5. The tractor unit 5 has the three tractor modules 101, 102, 103 fixed to a box-shaped base 90. The tractor unit 5 also has a lever 92 that is used to select any one of the three tractor modules 101, 102, 103. The tractor unit 5 feeds the continuous paper 2 to the printer unit 10 using the tractor module selected by operating the lever 92. The lever 92 can be moved in the direction of arrow A inside a slot 91 formed in the base 90.

The tractor unit 5 is attached to the top of the rear tractor unit 17 disposed at the back of the printer unit 10. The tractor unit 5 is removably attached to the printer unit 10. For example, the tractor unit 5 is affixed to the rear tractor unit 17 or to the case 12 of the printer unit 10.

The rear tractor unit 17 is disposed to the back end part of the printer unit 10, and feeds the continuous paper 2 into the printer unit 10. By using this rear tractor unit 17, the printer 1 can record on continuous paper 2 even when the tractor unit 5 is not installed.

The configuration of the printer 1 when the tractor unit 5 is not installed is described next.

FIG. 2 is an oblique view from the back of the printer unit 10 when the tractor unit 5 is not installed. FIG. 3 is a section view showing main parts of the internal configuration of the printer unit 10. The conveyance path through which the continuous paper 2 is conveyed is indicated by reference numeral W in the section view in FIG. 3.

As shown in FIG. 2, the rear tractor unit 17 disposed to the back end of the printer unit 10 pulls the continuous paper 2 located behind or below the printer unit 10 up in the direction of arrow B. The rear tractor unit 17 feeds the continuous paper 2 as it is pulled up into the paper feed entrance 18 formed in the back of the printer unit 10, and feeds the continuous paper 2 into the printer unit 10.

The rear tractor unit 17 has a pair of left and right tractors 20 that engage the sprocket holes 2 a in the sides of the continuous paper 2. The rear tractor unit 17 also has a tractor drive shaft 21 and a follower shaft 22. The tractor drive shaft 21 and follower shaft 22 pass through the pair of tractors 20. Note that the pair of left and right tractors 20 are symmetric left and right.

As shown in FIG. 3, each tractor 20 has a drive sprocket 23 that is turned by the tractor drive shaft 21, a follower sprocket 24 disposed with the follower shaft 22 passing therethrough, an endless tractor belt 25 that is mounted on the drive sprocket 23 and follower sprocket 24, and a case 27 that houses the drive sprocket 23, follower sprocket 24, and tractor belt 25. A plurality of tractor pins 26 protrude at an equal interval from the tractor belt 25. The distance between adjacent tractor pins 26 is substantially equal to the distance between the sprocket holes 2 a in the continuous paper 2.

When the tractor drive shaft 21 turns, the drive sprocket 23 turns therewith and the tractor belt 25 is conveyed. As a result, the tractor pins 26 move forward in the direction of arrow D or reverse in the direction of arrow E in FIG. 3.

A long channel (not shown in the figure) through which the tractor pins 26 protrude vertically is formed in the case 27. The tractor pins 26 move inside this channel. A cover 28 that can open and close is also attached to the case 27. The cover 28 is urged to the case 27 by a spring or other urging member (not shown in the figure). The cover 28 can be opened by operating a lever 29. When the continuous paper 2 is placed on the case 27 so that the tractor pins 26 pass through the sprocket holes 2 a and the cover 28 is then closed, the continuous paper 2 is held between the case 27 and cover 28. When the tractor drive shaft 21 turns with the continuous paper 2 held between the case 27 and cover 28, the tractor belt 25 is driven by the drive sprocket 23, the tractor pins 26 move, and the continuous paper 2 is conveyed.

The tractor drive shaft 21 is connected through a drive gear train to a paper feed motor 59 (FIG. 4) located inside the printer unit 10. The tractor drive shaft 21 is rotationally driven forward by the forward rotation (rotation in the direction of arrow D in FIG. 3) of the paper feed motor 59 shaft. The tractor drive shaft 21 is rotationally driven in reverse by the reverse rotation (rotation in the direction of arrow E in FIG. 3) of the paper feed motor 59 shaft.

As shown in FIG. 3, the printer unit 10 also has a main frame including a top frame member 41, bottom frame member 42, rear frame member 43, and left and right side frame members not shown. Parts of the printer unit 10 are supported by this main frame.

A conveyance path W that communicates with the paper feed entrance 18 is formed in the printer unit 10 by top paper guides 45, 46, and bottom paper guide 47. A paper detector 48 that detects the continuous paper 2 in the conveyance path W is disposed on the front side of the bottom paper guide 47. The paper detector 48 is a sensor switch. More specifically, the paper detector 48 includes a lever-like member that can pivot on a pin 49 affixed to the main frame described above, and a detection circuit that detects when this member contacts and is pivoted by the continuous paper 2 fed from the paper feed entrance 18. When the continuous paper 2 is not on the conveyance path W, the paper detector 48 is at the down position shown in FIG. 3. When the continuous paper 2 is on the conveyance path W, the paper detector 48 pivots up in FIG. 3 on the pin 49. The detection state of the paper detector 48 (whether or not continuous paper 2 is on the conveyance path W) is output to a control unit 70 (FIG. 4) described below.

The position in which the continuous paper 2 is on the conveyance path W and in contact with the paper detector 48 is detection position P1.

A first conveyance unit 50 that conveys the continuous paper 2, and paper guides 53, 54 that guide the continuous paper 2 to the first conveyance unit 50, are disposed on the front side of the paper detector 48. The first conveyance unit 50 includes a drive roller 51 that is driven by the paper feed motor 59 described below (FIG. 4), and a follower roller 52 that turns in contact with the drive roller 51. The first conveyance unit 50 holds the continuous paper 2 between the drive roller 51 and follower roller 52, and conveys the continuous paper 2 to the front by driving the drive roller 51 and the rotation of the follower roller 52 therewith.

A carriage 30 that carries the recording head 31, and a platen 33 disposed opposite the recording head 31 with the conveyance path W therebetween, are disposed on the downstream side, that is, the front side, of the first conveyance unit 50. The carriage 30 is mounted on a carriage guide shaft 34 mounted between the side frame members of the printer unit 10, and travels widthwise to the continuous paper 2 on the carriage guide shaft 34. The recording head 31 has an ejection mechanism that ejects the CMYK inks from nozzles disposed facing the platen 33. Ink supply lines that supply ink from the four ink cartridges stored inside the doors 14 (FIG. 1) are connected to this ejection mechanism. Ink is deposited and text and images are formed on the recording surface of the continuous paper 2 by ejecting ink from the recording head 31 while moving the carriage 30.

A carriage drive motor 55 is disposed above the top paper guide 46. A drive pulley 56 is mounted on the output shaft of the carriage drive motor 55. The drive pulley 56 is located at one end of the scanning range of the carriage 30. A follower pulley (not shown in the figure) is disposed at the other end of the carriage 30 scanning range. An endless carriage drive belt 35 is mounted on the follower pulley and the drive pulley 56. The carriage 30 is fastened to the carriage drive belt 35, and is moved bidirectionally over the platen 33 by operating the carriage drive motor 55.

The platen 33 is fastened to a support stand 38 that is supported pivotably to the printer unit 10. The support stand 38 can pivot on a support shaft 37, which is affixed to the left and right side frame members. The platen 33 moves vertically as the support stand 38 pivots. As a result, the gap between the nozzles of the recording head 31 and the continuous paper 2 can be optimally adjusted.

A second conveyance unit 57 and a third conveyance unit 58 that convey the continuous paper 2 are disposed on the front side of the recording head 31. The second conveyance unit 57 and third conveyance unit 58 each have a drive roller and a follower roller disposed in opposition above and below the conveyance path W. The second conveyance unit 57 and third conveyance unit 58 convey the continuous paper 2 in the direction of arrow C toward the paper exit 11.

FIG. 4 is a function block diagram showing the configuration of the printer 1 control system.

The printer 1 has a control unit 70 that centrally controls other parts of the printer 1. Hardware components of the control unit 70 include a CPU that runs programs, ROM that nonvolatilely stores software such as the control program run by the CPU, and RAM that temporarily stores process data and programs run by the CPU. The control unit 70 controls and maintains parts of the printer 1 in an operable state, and controls printing according to control data sent from a host computer 8 externally connected to the printer 1.

The control unit 70 includes a recording control unit 71 that controls the operation whereby the printer 1 records text and images on the continuous paper 2. The control unit 70 also has a tractor drive control unit 72 that controls operation of the rear tractor unit 17 and/or the tractor unit 5 when the tractor unit 5 is installed to the printer unit 10.

The paper detector 48, a rotary encoder 74, head driver 75, motor driver 76, motor driver 77, and the switches and indicators of the operating panel 16 are connected to the control unit 70.

The head driver 75 drives the recording head 31 and ejects ink as controlled by the control unit 70. The motor driver 76 drives the paper feed motor 59 forward or reverse as controlled by the control unit 70. The motor driver 77 drives the carriage drive motor 55 forward or reverse as controlled by the control unit 70.

An interface 78 connected to the host computer 8 is also connected to the control unit 70. The control unit 70 receives control data and recording data sent by the host computer 8 through the interface 78.

The rotary encoder 74 detects the amount of rotation of at least one gear in the drive gear train that conveys drive power from the paper feed motor 59. For example, the rotary encoder 74 detects the amount of rotation of the tractor drive gear 96 that transfers drive power to the tractor modules 101, 102, 103 of the tractor unit 5, or detects the amount of rotation of the transfer gear 97 (FIG. 8) that transfer drive power from the paper feed motor 59 to the tractor drive gear 96.

A rotary encoder 74 (FIG. 4) that detects the rotation of the drive sprocket 23 is attached to the drive sprocket 23. The rotation of the drive sprocket 23 detected by the rotary encoder 74 is output to the control unit 70 (FIG. 4).

The control unit 70 controls ink ejection from the recording head 31 by controlling the head driver 75. The control unit 70 operates the paper feed motor 59 by controlling the motor driver 76. The drive roller 51 of the first conveyance unit 50, and the drive rollers of the second conveyance unit 57 and third conveyance unit 58, are connected through a drive gear train (not shown in the figure) to the output shaft of the paper feed motor 59. These drive rollers are driven as controlled by the control unit 70 to convey the continuous paper 2.

The tractor drive shaft 21 is also connected directly or through the transfer gear 97 or other gear to the drive gear train of the paper feed motor 59. As a result, the rear tractor unit 17 operates in conjunction with the first conveyance unit 50, second conveyance unit 57, and third conveyance unit 58 to convey the continuous paper 2 by the drive power from the paper feed motor 59. The control unit 70 also controls the motor driver 77 to drive the carriage drive motor 55 and move the carriage 30 bidirectionally over the platen 33. The control unit 70 also detects operation of switches on the operating panel 16. The control unit 70 also controls operation of the indicators on the operating panel 16 according to the operating state of the printer 1.

When control data including a command to start recording (printing) and the data to be recorded is received from the host computer 8, the control unit 70 controls the printer 1 by functions of the recording control unit 71. The recording control unit 71 acquires the output value of the paper detector 48, and determines if continuous paper 2 is in the conveyance path W. If the continuous paper 2 is in the conveyance path W, the recording control unit 71 drives the paper feed motor 59 and conveys the continuous paper 2 to the recording position of the recording head 31. The recording control unit 71 then drives the carriage drive motor 55 to move the carriage 30 bidirectionally while operating the recording head 31 to record on the continuous paper 2. The recording control unit 71 also operates the paper feed motor 59 to appropriately advance and discharge the paper.

When the tractor unit 5 is installed to the printer 1, the tractor drive control unit 72 controls the operation that selects the tractor module to use from among the plural tractor modules 101, 102, 103 in the tractor unit 5, and the operation that switches to a different tractor after a tractor is selected. When a tractor module has been selected from among the plural tractor modules 101, 102, 103, the tractor drive control unit 72 drives the tractor module and conveys the continuous paper 2 by controlling operation of the paper feed motor 59.

FIG. 5 is an oblique view from the back of the printer 1 when the tractor unit 5 is installed. FIG. 6 is an oblique view of main parts in the configuration of the tractor module 101. While described in further detail below, the size of the frame 111, 112, 113 of the tractor modules 101, 102, 103 may differ. Other than the size of the frame 111, 112, 113, the tractor modules 101, 102, 103 are otherwise identical, and FIG. 6 shows the configuration of tractor module 101 as an example.

As described above, the tractor unit 5 has three tractor modules 101, 102, 103 that are stacked one above the other when used. The tractor modules 101, 102, 103 are disposed to a generally box-like base 90 with the part facing the paper feed entrance 18 of the printer unit 10 U-shaped. The tractor modules 101, 102, 103 may be fastened to the base 90, but in this embodiment are removably installed to the base 90. Three slots sized to accommodate the tractor modules 101, 102, 103 are formed inside the U-shaped part of the base 90. The tractor modules 101, 102, 103 are installed to the base 90 by sliding them into these slots in the direction of arrows L, M, N in FIG. 5. To remove the tractor modules 101, 102, 103 from the base 90, the tractor modules 101, 102, 103 are simply slid and pulled out in the opposite direction as arrows L, M, N.

The tractor modules 101, 102, 103 respectively have a frame 111, 112, 113. Each tractor module 101, 102, 103 has a pair of left and right tractors 120, 130 (conveyance units) that convey the continuous paper 2 on the inside of the frame 111, 112, 113. The frame 111 is an angular frame enclosing the sides and back of the tractor module 101. The frame 111 is open on the front side of the tractor module 101. Frames 112 and 113 likewise enclose the sides and back of the respective tractor module 102, 103.

The pair of tractors 120, 130 are disposed at the front of the frame 111. Tractor 120 and tractor 130 are symmetrical left and right. The tractor module 101 has a tractor drive shaft 115 and follower shaft 116 that pass through the tractors 120, 130. Frames 112 and 113 likewise have a pair of tractors 120, 130 at the front, and a tractor drive shaft 115 and follower shaft 116 that pass through the tractors 120, 130.

The tractor 120 has a case 121. A drive sprocket (not shown in the figure) that is driven by rotation of the tractor drive shaft 115, a follower sprocket (not shown in the figure) disposed with the follower shaft 116 passing therethrough, and an endless tractor belt 123 mounted on the drive sprocket and follower sprocket are housed inside the case 121. A plurality of tractor pins (not shown in the figure) that engage the sprocket holes 2 a protrude at an equal interval from the tractor belt 123. A cover 125 that can open and close on a hinge is attached to the top of the case 121. The continuous paper 2 is held between the cover 125 and case 121, and conveyed by the pins. The cover 125 is urged to the case 121 by a spring or other urging member (not shown in the figure). The cover 125 can be opened by operating a lever 126 disposed to the case 121.

The tractor 130 is left and right symmetrical to the tractor 120. The tractor 130 has a case 131. A drive sprocket (not shown in the figure) that is driven by rotation of the tractor drive shaft 115, a follower sprocket (not shown in the figure) disposed with the follower shaft 116 passing therethrough, and an endless tractor belt 133 mounted on the drive sprocket and follower sprocket are housed inside the case 131. A plurality of tractor pins (not shown in the figure) that engage the sprocket holes 2 a protrude at an equal interval from the tractor belt 133. A cover 135 that can open and close on a hinge is attached to the top of the case 131. The continuous paper 2 is held between the cover 135 and case 131, and conveyed by the pins. The cover 135 is urged to the case 131 by a spring or other urging member (not shown in the figure). The cover 135 can be opened by operating a lever 136 disposed to the case 131.

As shown in FIG. 6, a gear 117 is attached to the tractor drive shaft 115. As described below, torque is applied to the gear 117 and the tractor drive shaft 115 turns when the drive power of the paper feed motor 59 is transferred from the printer unit 10 side to the gear 117. As a result, the drive sprocket fixed to the tractor drive shaft 115 turns, and the tractors 120, 130 convey the continuous paper 2. The tractors 120, 130 can convey the continuous paper 2 toward the printer unit 10, or in the opposite direction as the conveyance direction toward the printer unit 10, by changing the direction that the paper feed motor 59 turns. The plural tractor modules 101, 102, 103 of the tractor unit 5 operate exclusively of each other. When one of the tractor modules 101, 102, 103 is selected by the user, only the one tractor module that was selected conveys continuous paper 2. The other tractor modules do not operate while the one selected tractor module is conveying the continuous paper 2.

FIG. 7 is an oblique view showing the internal configuration of the tractor unit 5 in detail. FIG. 8 is a section view showing the configuration of the printer 1 when the tractor unit 5 is installed.

As shown in FIG. 8, the position from which the continuous paper 2 is discharged from the tractors 120, 130 of tractor module 101 is discharge position P11. The position to which the continuous paper 2 is fed from the tractors 120, 130 of tractor module 102 is discharge position P12. The position to which the continuous paper 2 is fed from the tractors 120, 130 of tractor module 103 is discharge position P13.

As shown in FIG. 7 and FIG. 8, a divider 94 that separates the tractor unit 5 and the rear tractor unit 17 is located below the tractor unit 5. The divider 94 is a substantially L-shaped sheet member having a horizontal portion that covers the top of the tractor 20 of the rear tractor unit 17 connected to a vertical portion that covers the back of the rear tractor unit 17. The divider 94 extends substantially horizontally above the tractor 20 along the conveyance path of the continuous paper 2. The distal end (one end) of the divider 94 extends almost to the paper feed entrance 18 or to the inside of the paper feed entrance 18. The other end side of the divider 94 extends substantially vertically along the back of the rear tractor unit 17, and the bottom end (other end) of the divider 94 extends below the bottom end of the rear tractor unit 17. As shown in FIG. 5, the bottom end of the divider 94 could also bend toward the printer unit 10 with the bottom end extending to the bottom of the printer unit 10. The divider 94 prevents the continuous paper 2 from contacting the tractor 20 of the rear tractor unit 17 when the tractor unit 5 conveys the continuous paper 2. The divider 94 is also part of the continuous paper 2 conveyance path as described below.

The tractor unit 5 has two guide plates 201, 202 that extend from the discharge position P11 toward the paper feed entrance 18. The guide plates 201, 202 are parallel to each other. The distal ends of the guide plates 201, 202 extend proximally to the paper feed entrance 18 or to the inside of the paper feed entrance 18. Because the tractor module 101 is located at the top of the tractor unit 5 at a position above the paper feed entrance 18, the guide plates 201, 202 slope down from the discharge position P11 toward the paper feed entrance 18. Continuous paper 2 fed from tractors 120, 130 enters the space 203 between guide plate 201 and guide plate 202, and is guided through this space 203 to the paper feed entrance 18. More specifically, this space 203 is part of the continuous paper 2 conveyance path. Because the distal ends of the guide plates 201, 202 extend at a downward angle toward the paper feed entrance 18, the continuous paper 2 fed through the space 203 enters the printer unit 10 at a downward angle. The distal end of guide plate 202 is positioned above the divider 94. More specifically, the continuous paper 2 rides onto the divider 94 before the paper feed entrance 18, and then travels from the distal end of the divider 94 into the paper feed entrance 18. As a result, the tractor module 101 positioned above the tractor 20 enables the conveyed continuous paper 2 to be fed smoothly into the printer unit 10.

The tractor unit 5 has also two guide plates 204, 205 that extend from the discharge position P12 toward the paper feed entrance 18. The guide plates 204, 205 are parallel to each other. The distal ends of the guide plates 204, 205 are opposite the divider 94 at a position upstream from the paper feed entrance 18. A space 206 that becomes the path through which the continuous paper 2 is conveyed is formed between guide plate 204 and guide plate 205.

Another guide plate 207 connects the distal end of the one guide plate 204 and the distal end of the guide plate 202 located thereabove. This guide plate 207 is disposed above and substantially parallel to the divider 94. The space between the guide plate 207 and the divider 94 communicates with space 206, and forms part of the continuous paper 2 conveyance path. As a result, the continuous paper 2 fed from the discharge position P12 is conveyed between the guide plates 204, 205 and down, and then contacts and is conveyed substantially parallel to the divider 94.

Because the guide plate 207 is connected to the distal end of the guide plate 202, the conveyance path below the guide plate 207 merges with space 203. This merging position is referred to as position P3. As a result, the continuous paper 2 conveyed between the guide plate 207 and divider 94 enters the paper feed entrance 18 through the same path as the continuous paper 2 conveyed by tractor module 101.

The tractor unit 5 has another guide plate 208 extending from discharge position P13 toward the paper feed entrance 18. This guide plate 208 is parallel to the divider 94. The space between the guide plate 208 and divider 94 forms a path for conveying the continuous paper 2 fed from the discharge position P13. The continuous paper 2 conveyed through the path between the guide plate 208 and divider 94 is guided over the top of the divider 94 to the paper feed entrance 18. The distal end of guide plate 208 connects to the distal end of guide plate 205. More specifically, the space between the guide plate 208 and divider 94 communicates with the space between guide plate 204 and guide plate 205. As a result, the conveyance path of the continuous paper 2 connected to the discharge position P13 merges into the conveyance path communicating with the discharge position P12. This merging position is position P2.

As described above, the tractor unit 5 has conveyance paths that guide continuous paper 2 conveyed from each of the tractor modules 101, 102, 103 to the paper feed entrance 18, and these paths merge at positions P2 and P3. As a result, whichever one of the tractor modules 101, 102, 103 conveys the continuous paper 2, the continuous paper 2 ultimately passes through the same path from the paper feed entrance 18 into the printer unit 10. The continuous paper 2 therefore enters the nipping part of the first conveyance unit 50 at substantially the same angle regardless of which tractor module 101, 102, 103 conveys the continuous paper 2. The load on the first conveyance unit 50 is therefore kept substantially constant.

The tractor unit 5 is also configured so that the conveyance distance from each of the discharge positions P11, P12, P13 to the position P3 where all of the conveyance paths converge is the same. This can be achieved by adjusting the size and angle of the guide plates 201, 202, 204, 205, 207, 208, and the positions of the tractors 120, 130 in each of the tractor modules 101, 102, 103.

The conveyance distance is the same from position P3 to each of the discharge positions P11, P12, P13. More specifically, the distance is also the same from each of the discharge positions P11, P12, P13 to the detection position P1. As a result, the conveyance distance until the continuous paper 2 is detected by the paper detector 48 after the continuous paper 2 is fed from the tractors 120, 130 is therefore constant regardless of which tractor module 101, 102, 103 is used. The distance that the continuous paper 2 inside the printer unit 10 is conveyed by each of the tractor modules 101, 102, 103 to the outside of the printer unit 10 is also the same regardless of which tractor module is used. As a result, the tractor drive control unit 72 (FIG. 4) that controls the printer 1 can start conveying the continuous paper 2 toward the printer unit 10, and can recover the continuous paper 2 from the printer unit 10, without knowing which of the tractor modules 101, 102, 103 is used.

Furthermore, regardless of which tractor module 101, 102, 103 is used, the continuous paper 2 ultimately passes through the same conveyance path to reach the first conveyance unit 50. More specifically, the contact angle of the continuous paper 2 to the drive roller 51 is constant. As a result, regardless of which tractor module 101, 102, 103 is used, the load on the drive roller 51 during media conveyance is constant. The continuous paper 2 can therefore be conveyed consistently. In addition, the continuous paper 2 conveyance path when the tractor unit 5 is used, and the conveyance path when the tractor 20 of the rear tractor unit 17 is used, merge into a common path at the paper feed entrance 18 or before. As a result, the load on the drive roller 51 is constant regardless of whether the tractor unit 5 or the tractor 20 of the rear tractor unit 17 is used. The continuous paper 2 can therefore be conveyed consistently regardless of which tractor is used.

A configuration enabling selectively and exclusively using the tractor modules 101, 102, 103 is described next.

The printer unit 10 has a transfer gear 97 that connects directly or through a drive gear train (not shown in the figure) to the output shaft of the paper feed motor 59 (FIG. 4). A tractor drive gear 96 meshes with the transfer gear 97. The tractor drive gear 96 can move along an arc while meshed with the transfer gear 97.

Driven gear 151, driven gear 152, and driven gear 153 are also disposed to the base 90 of the tractor unit 5. Driven gear 151 meshes with gear 117 of tractor module 101. Driven gear 152 meshes with gear 117 of tractor module 102. Driven gear 153 meshes with gear 117 of tractor module 103. The driven gears 151, 152, 153 are attached freely rotationally to the base 90 at positions where they do not contact each other.

In this embodiment, the driven gears 151, 152, 153 mesh directly with the gear 117 of the corresponding tractor module 101, 102, 103. While not shown in the figures, the driven gears 151, 152, 153 could also be configured to transfer drive power to the gear 117 through one or a plurality of gears.

As described above, the tractor modules 101, 102, 103 can be removably installed to the base 90. The tractor modules 101, 102, 103 are installed to the base 90 by inserting them in the direction of arrows L, M, N in FIG. 5. The gear 117 of each tractor module 101, 102, 103 protrudes from the distal end of the corresponding frame 111, 112, 113. As a result, when the tractor module 101, 102, 103 is installed to the base 90, the gear 117 protruding in front of the tractor module 101, 102, 103 contacts and meshes with the corresponding driven gear 151, 152, 153 on the base 90 side. The tractor modules 101, 102, 103 can be driven by holding the tractor modules 101, 102, 103 in this position so that they do not slip out of the base 90.

The tractor drive gear 96 can then be selectively meshed with one of the driven gears 151, 152, 153 by moving the tractor drive gear 96.

FIG. 9A to FIG. 9C describe in detail the configuration for moving the tractor drive gear 96. FIG. 9A is an oblique view of essential parts showing movement of the tractor drive gear 96. FIG. 9B is a side section view showing movement of the tractor drive gear 96. FIG. 9C is an oblique view showing movement of the tractor drive gear 96 from the opposite side shown in FIG. 9A.

A selection wheel 93 is disposed rotatably to the base 90. The selection wheel 93 moves in unison with the lever 92 that protrudes from the top of the base 90. The axis of rotation 93 a of the selection wheel 93 is shown in FIG. 9C. The position of the axis of rotation 93 a matches the center of the round selection wheel 93. Any suitable configuration can be used to support the selection wheel 93 rotatably on the base 90.

The selection wheel 93 is disposed to the end of one side of the base 90 so that the selection wheel 93 is at the side of the tractor modules 101, 102, 103. The selection wheel 93 is connected by a connecting rod 95 to the tractor drive gear 96 disposed on the other side of the base 90. The tractor drive gear 96 is disposed so that it can move along an arc-shaped path relative to the base 90 as described above.

As shown in FIG. 9A, the connecting rod 95 is affixed at the center of the round tractor drive gear 96. As shown in FIG. 9B and FIG. 9C, the other end of the connecting rod 95 is affixed to the selection wheel 93 at an eccentric position offset from the axis of rotation 93 a of the selection wheel 93. As shown in FIG. 9A, the selection wheel 93 turns when the lever 92 is operated and moves to positions 92A and 92B. The connecting rod 95 moves in a twisting action to positions 95A and 95B in conjunction with rotation of the selection wheel 93. This movement of the connecting rod 95 is transferred to the tractor drive gear 96, and the tractor drive gear 96 moves in an arc to positions 96A and 96B as indicated by the dotted lines in the figures.

The tractor drive gear 96 meshes with driven gear 151 when in the position indicated by the solid line in FIG. 9A. In this position, drive power from the paper feed motor 59 (FIG. 4) is transferred to the tractor drive shaft 115 of tractor module 101.

At position 96A, the tractor drive gear 96 meshes with driven gear 152. As a result, drive power from the paper feed motor 59 is transferred to the tractor drive shaft 115 of tractor module 102.

At position 96B, the tractor drive gear 96 meshes with driven gear 153. As a result, drive power from the paper feed motor 59 is transferred to the tractor drive shaft 115 of tractor module 103.

The driven gears 151, 152, 153 are also positioned so that plural driven gears do not mesh with the tractor drive gear 96 at the same time. As a result, only one of the tractor modules 101, 102, 103 is selected and driven at any time.

Drive power from the paper feed motor 59 is thus transferred by this configuration through a common drive gear train including the tractor drive gear 96 to one of the driven gears 151, 152, 153. As a result, a constant amount of drive power is transferred to whichever driven gear 151, 152, 153 is selected. As a result, there is no variation in the drive power transferred from the paper feed motor 59 to each of the driven gears 151, 152, 153. There is, therefore, also no need to compensate for variation in the drive power on the paper feed motor 59 side that drives the tractor drive gear 96. The tractor unit 5 can therefore convey the continuous paper 2 stably using a simple configuration.

In addition, the driven gear 151, 152, 153 that is driven can be easily changed by the simple operation of moving the lever 92 to rotate the selection wheel 93. The driven gear can be changed even more easily by providing a mechanism that holds the selection wheel 93 at the position to which it is rotated at each position where the transfer gear 97 meshes with one of the driven gears 151, 152, 153.

When the tractor module to be used is selected from among the group of tractor modules 101, 102, 103 by operating the lever 92, the tractor drive control unit 72 (FIG. 4) executes an operation that changes the continuous paper 2 to be conveyed. This operation of changing the continuous paper 2 may be performed automatically by detecting the pressure applied to the lever 92. The operation of changing the continuous paper 2 may also be initiated by operating a switch on the operating panel 16 or in response to a command sent from the host computer 8 to the printer 1.

In this operation, the tractor drive control unit 72 first drives the paper feed motor 59 in reverse to recover the continuous paper 2 inside the printer unit 10 with the tractors 120, 130. Drive power from the paper feed motor 59 is transferred through the tractor drive gear 96 to the tractor module being used at this time even without the tractor drive control unit 72 knowing which tractor module is being used. The tractor drive control unit 72 can thus recover the continuous paper 2 from inside the printer unit 10.

When the continuous paper 2 recovery operation starts, the tractor drive control unit 72 starts monitoring the output value of the paper detector 48. When the leading end of the continuous paper 2 is detected by the paper detector 48 after recovering the continuous paper 2 starts, the tractor drive control unit 72 starts counting the amount of continuous paper 2 that is recovered from that time. The tractor drive control unit 72 counts while continuing the continuous paper 2 recovery operation. When the amount of continuous paper 2 recovered reaches a specific count, the tractor drive control unit 72 stops the paper feed motor 59. This specific amount (count) is equal to the distance the continuous paper 2 is conveyed from the detection position P1 of the paper detector 48 to the discharge positions P11, P12, P13. Because this amount is equal to the distance from the detection position P1 to the discharge positions P11, P12, P13, the continuous paper 2 is recovered a constant amount regardless of which tractor module 101, 102, 103 is used.

When the tractor module 101, 102, 103 is changed, there is no need to remove the continuous paper 2 from the tractor modules because the continuous paper 2 inside the printer unit 10 only needs to be reversed to the discharge position P11, P12, P13.

As shown in FIG. 5 and FIG. 8, the back end of the frame 111 located at the highest position above the tractor unit 5 protrudes further to the back than frame 112. The back end of frame 112 also protrudes further to the back than frame 113. A guide hole (paper feed guide) 111 a, 112 a, 113 a through which the continuous paper 2 passes is formed in each of the frames 111, 112, 113.

These guide holes 111 a, 112 a, 113 a are slots that are longer than the width of the widest paper that can be loaded in the tractors 120, 130, and extend widthwise to the continuous paper 2. Different widths of continuous paper 2 can be used in the tractor modules 101, 102, 103. As a result, the guide holes 111 a, 112 a, 113 a are preferably longer than the width of continuous paper 2 that can be used in that particular tractor module. For example, the guide hole 111 a formed in tractor module 101 is longer than the width of the continuous paper 2 that can be used in tractor module 101. This also applies to guide holes 112 a and 113 a.

As shown in FIG. 8, the continuous paper 2 (indicated by dotted lines) that can be supplied from below the bottom of the back of the printer 1 passes through the guide holes 111 a, 112 a, 113 a. The continuous paper 2 passing through the guide holes 111 a, 112 a, 113 a is set from above into the corresponding tractors 120, 130, and supplied to the paper feed entrance 18. Each of the guide holes 111 a, 112 a, 113 a is at a different horizontal distance from the paper feed entrance 18. As a result, as indicated by the dotted lines in FIG. 8, the continuous paper 2 b passing through guide hole 111 a, the continuous paper 2 c passing through guide hole 112 a, and the continuous paper 2 d passing through guide hole 113 a do not touch each other. There is, therefore, no chance of conveyance problems caused by friction between the different continuous paper 2 in the tractor unit 5 even when continuous paper 2 is loaded in each of the tractor modules 101, 102, 103. The tractor unit 5 can therefore convey the continuous paper 2 reliably and consistently.

As shown in FIG. 8, guide hole 112 a is positioned further to the back than the back end of frame 113. Guide hole 111 a is also positioned further to the back than the back ends of frame 112 and frame 113. When thus configured, the likelihood of the continuous paper 2 b passing through guide hole 111 a contacting frame 112 is low, and the likelihood of the continuous paper 2 c passing through guide hole 112 a contacting frame 113 is low. There is, therefore, no chance of conveyance problems in the tractor unit 5 resulting from friction between the continuous paper 2 and frame 112 or frame 113. The tractor unit 5 can therefore convey the continuous paper 2 more consistently.

As described above, the tractor modules 101, 102, 103 that feed continuous paper 2 in a printer 1 according to the first embodiment of the invention each have a gear 117 that is driven by drive power from the paper feed motor 59 on the printer unit 10 side, tractors 120, 130 that convey the continuous paper 2 in a specific direction according to rotation of the gear 117, and a frame 111, 112, 113 that guides the continuous paper 2 supplied from an external source to the tractors 120, 130. The tractor modules 101, 102, 103 guide the conveyed continuous paper 2 with the respective frame 111, 112, 113. As a result, contact between the continuous paper 2 separately conveyed by the plural tractor modules 101, 102, 103 can be avoided. Plural tractor modules 101, 102, 103 can also be disposed in close proximity to each other in a single printer 1.

A guide hole 111 a, 112 a, 113 a through which the continuous paper 2 passes is also formed in the frame 111, 112, 113. Movement of the continuous paper 2 is limited by passing through the guide hole 111 a, 112 a, 113 a. Contact between the continuous paper 2 conveyed by each tractor module 101, 102, 103 can therefore be avoided even when the plural tractor modules 101, 102, 103 are disposed close to each other.

A tractor unit 5 having a base 90 that removably holds the tractor modules 101, 102, 103, and a printer 1 having this tractor unit 5, guide the continuous paper 2 conveyed by the plural tractor modules 101, 102, 103 with the frames 111, 112, 113. Contact between the continuous paper 2 conveyed by each tractor module 101, 102, 103 can therefore be avoided. A printer 1 having plural tractor modules 101, 102, 103 disposed close to each other can therefore be provided.

Embodiment 2

FIG. 10A is an oblique view from the front, and FIG. 10B is an oblique view from the back, of a tractor module 301 according to a second embodiment of the invention. Note that like parts in this second embodiment and the first embodiment described above are identified by like reference numerals, and further description thereof is omitted or simplified.

Like the tractor modules 101, 102, 103 described above, this tractor module 301 (tractor) has tractors 120, 130. The tractor module 301 conveys continuous paper 2 toward the paper feed entrance 18 by means of the tractors 120, 130.

This tractor module 301 has a rectangular frame 311. This rectangular frame 311 has a front crosspiece 311 d located in front of the tractors 120, 130. The frame 311 is fit into a channel (not shown in the figure) in the base 90 and thereby removably supported on the base 90 similarly to the tractor modules 101, 102, 103 described above. The continuous paper 2 fed by the tractors 120, 130 passes over the front crosspiece 311 d and is fed into the paper feed entrance 18 as indicated by the arrow in FIG. 10.

The tractor module 301 has a gear 118. Drive power is transferred to the gear 118 from the paper feed motor 59 on the printer unit 10 side. The gear 118 is exposed below the bottom of the frame 311. The tractor drive shaft 115 passes through the center of the gear 118. When the gear 118 is turned by drive power transferred from the paper feed motor 59 on the printer unit 10 side, the tractor drive shaft 115 turns and the tractors 120, 130 are driven. A gear (not shown in the figure) meshes with the gear 118 from below the tractor module 301. As a result, drive power from the paper feed motor 59 on the printer unit 10 side can be transferred to the gear 118.

To use the tractor module 301, one of the driven gears 151, 152, 153 on the base 90 is therefore positioned to the gear 118. Any one of the driven gears 151, 152, 153 can be meshed with the gear 118 to transfer drive power from the paper feed motor 59 on the printer unit 10 side. When three tractor modules 301 are installed to the base 90, one of the driven gears 151, 152, 153 is positioned to each of the three tractor modules 301.

The tractors 120, 130 of this tractor module 301 are enclosed on the front and back, left and right sides by the frame 311. This makes handling easier by simply holding the frame 311. This tractor module 301 can therefore be easily removed from the base 90 or installed to the base 90 while the continuous paper 2 remains loaded in the tractor module 301.

A guide hole 311 a (feed-side guide) is also formed in the cross member forming the back end of the frame 311. The continuous paper 2 that is pulled up by the tractors 120, 130 from below is inserted to this guide hole 311 a. The guide hole 311 a is longer than the width of the continuous paper 2 that can be loaded in the tractors 120, 130, and extends widthwise to the continuous paper 2. The continuous paper 2 is supplied through this guide hole 311 a to the tractors 120, 130. The orientation of the continuous paper 2 is thereby restricted at the back side of the tractor module 301. The continuous paper 2 is thus prevented from skewing or bulging up greatly above or to the back. When plural tractor modules 301 are stacked one above the other instead of the tractor modules 101, 102, 103 shown in FIG. 8, contact between the continuous paper 2 pulled up by each of the tractor modules 301 is prevented. A printer 1 using this tractor module 301 can therefore convey the continuous paper 2 consistently.

The corner 311 b at the top rear part of the frame 311 is also rounded or beveled. As a result, the continuous paper 2 can be prevented from snagging the back end of the frame 311 in the event continuous paper 2 conveyed by a separate higher tractor module 301 contacts the back edge of the frame 311 of a lower tractor module 301. The tractor unit 5 can therefore convey the continuous paper 2 more consistently when a plurality of tractor modules 301 are stacked in layers.

Embodiment 3

FIG. 11 is an oblique view from the front of a tractor module 303 according to a third embodiment of the invention. FIG. 12 is an oblique view of the tractor module 303 from the back. FIG. 13 shows the tractor module 303 in section. Note that like parts in this embodiment and the first and second embodiments described above are identified by like reference numerals, and further description thereof is omitted or simplified.

Like the tractor module 301 described above, this tractor module 303 (tractor) has a rectangular frame 313 that encloses the front and back, and left and right sides of the tractors 120, 130. A guide hole 313 a (feed-side guide) identical to the above guide hole 311 a is formed in the back part of the frame 313. The continuous paper 2 is supplied through this guide hole 313 a to the tractors 120, 130. The corner 313 b of the back top part of the frame 313 is also rounded or bevelled.

The frame 313 also has a front crossbar 313 e in front of the tractors 120, 130. A slot 313 f (discharge guide) is formed in this front crossbar 313 e. This slot 313 f is a hole that extends along the length of the front crossbar 313 e, that is, across the width of the continuous paper 2. The continuous paper 2 fed by the tractors 120, 130 is conveyed in the direction of the arrow in the figure through the slot 313 f.

As with the frame 311 (FIG. 10) described above, the frame 313 is fit into a channel (not shown in the figure) in the base 90 (FIG. 5), and is thus removably supported by the base 90. The tractor module 303 also has a gear 118 to which drive power from the paper feed motor 59 on the printer unit 10 side is transferred. The gear 118 is rotated by the drive power from the paper feed motor 59 on the printer unit 10 side. When the gear 118 turns, the tractor drive shaft 115 turns and the tractors 120, 130 are driven.

As shown in FIG. 13, the slot 313 f is formed through the front crossbar 313 e. The width (height) of the opening 313 g on the tractor 120, 130 side of the slot 313 f is greater than the width (height) of the opening 313 h on the side from which the continuous paper 2 is discharged. As a result, the leading end of the continuous paper 2 fed from the tractors 120, 130 is fed smoothly through the slot 313 f without any particular adjustment needed. Because the width of the opening 313 h is narrow, the continuous paper 2 is also fed to the paper feed entrance 18 without bouncing up and down inside the slot 313 f. The slot 313 f can thus limit movement of the continuous paper 2 to prevent interference with continuous paper 2 conveyance. The tractors 120, 130 can therefore convey the continuous paper 2 consistently to the paper feed entrance 18. When plural tractor modules 303 are installed to the base 90, collision between continuous paper 2 conveyed by different tractor modules 303 can be avoided, and the continuous paper 2 can be stably supplied to the printer unit 10.

Embodiment 4

FIG. 14 is an oblique view of a tractor module 305 according to a fourth embodiment of the invention. FIG. 15 is a section view of the tractor module 305. Note that like parts in this embodiment and the first to third embodiments described above are identified by like reference numerals, and further description thereof is omitted or simplified.

Like the tractor module 303 described above, the tractor module 305 (tractor) shown in FIG. 14 has a rectangular frame 315 that encloses the front and back, and left and right sides of the tractors 120, 130. The frame 315 has a front crossbar 315 e in front of the tractors 120, 130. A slot 315 f (discharge guide) is formed in this front crossbar 315 e. This slot 315 f is a hole that extends along the length of the front crossbar 315 e, that is, across the width of the continuous paper 2. The continuous paper 2 fed by the tractors 120, 130 is conveyed in the direction of the arrow in the figure through the slot 315 f.

As with the frame 311 (FIG. 10) described above, the frame 315 is fit into a channel (not shown in the figure) in the base 90 (FIG. 5), and is thus removably supported by the base 90. The tractor module 305 also has a gear 118. Drive power from the paper feed motor 59 on the printer unit 10 side is transferred to the gear 118. When the gear 118 is rotated and turned by drive power from the paper feed motor 59 on the printer unit 10 side, the tractor drive shaft 115 turns and the tractors 120, 130 are driven.

As shown in FIG. 15, the slot 315 f is formed through the front crossbar 315 e. The width (height) of the opening 315 g on the tractor 120, 130 side of the slot 315 f is greater than the width (height) of the opening 315 h on the side from which the continuous paper 2 is discharged. As a result, the leading end of the continuous paper 2 fed from the tractors 120, 130 is fed smoothly through the slot 315 f without any particular adjustment needed. Because the width of the opening 315 h on the discharge side of the slot 315 f is narrow, the continuous paper 2 is fed to the paper feed entrance 18 without bouncing up and down inside the slot 315 f.

A guide hole 315 a (paper feed guide) identical to guide hole 311 a, and a guide hole 315 d that is a wider slot than guide hole 315 a, are also formed in the back part of the cover frame 315. These guide holes 315 a and 315 d are parallel to each other with guide hole 315 a on the tractor 120, 130 side. The continuous paper 2 that is pulled up by the tractors 120, 130 is inserted to guide hole 315 a. The other guide hole 315 d is located behind guide hole 315 a. This guide hole 315 d is a slot for passing continuous paper 2 that is conveyed by a tractor module located above the tractor module 305 that has guide hole 315 d.

When plural tractor modules are installed one above the other as shown in FIG. 8, and tractor module 305 is used as the tractor module second from the top, the continuous paper 2 that is lifted by this tractor module 305 is guided by guide hole 315 a, and the continuous paper 2 that is lifted by the tractor module located above this tractor module 305 is guided through guide hole 315 d. As a result, there is no contact between the continuous paper 2 that is conveyed by separate tractor modules. Furthermore, because guide hole 315 a is narrow, the continuous paper 2 that is conveyed by tractors 120, 130 can be firmly controlled, and the continuous paper 2 can be prevented from billowing up due to the stiffness of the continuous paper 2. As a result, plural different streams of continuous paper 2 can be consistently supplied to a printer 1 that is installed in a confined space.

The corner 315 b of the back top part of the frame 315 is also rounded or bevelled. Resistance can therefore be reduced when continuous paper 2 is supplied to the tractor module located above this tractor module 305 and contacts the frame 315, and the continuous paper 2 can therefore be supplied consistently. Because the tractor module 305 thus has a guide hole 315 a through which the continuous paper 2 conveyed by that tractor module 305 passes, a guide hole 315 d through which the continuous paper 2 conveyed by the tractor module located above that tractor module 305 passes, and a rounded or beveled corner 315 b at the top back end of the frame 315, the tractor unit 5 can consistently supply continuous paper 2 when plural tractor modules are installed thereto one above the other.

Embodiment 5

FIG. 16 is an oblique view from the front of a printer 100 described as an example of a recording device according to a fifth embodiment of the invention. FIG. 17 is an oblique view of the printer 100 from the back (rear). The outside case 701 is indicated by an imaginary line in FIG. 17. FIG. 18 is an oblique view of the printer 100 with the outside case 701 removed. Note that like parts in this embodiment and the first embodiment described above are identified by like reference numerals, and further description thereof is omitted or simplified.

As shown in FIG. 16, a paper feed entrance 18 is open in the back of the printer unit 10. The printer 100 records with a recording head 31 described below on the continuous paper 2 conveyed from the paper feed entrance 18.

A rear tractor unit 17 is disposed to the printer unit 10. The rear tractor unit 17 conveys continuous paper 2 supplied from below the printer unit 10 at the back to the paper feed entrance 18. This rear tractor unit 17 and a separate tractor unit 7 are used exclusively of each other. More specifically, the rear tractor unit 17 is used when the tractor unit 7 is not installed to the printer unit 10. The rear tractor unit 17 is not used when the tractor unit 7 is installed to the printer unit 10.

The tractor unit 7 has an outside case 701 that covers the back of the printer unit 10. The tractor unit 7 has a elevator unit 710, and a lift mechanism 700 that raises and lowers the lift unit 710, disposed inside the outside case 701. The lift unit 710 has a pair of left and right frames 715, 717 that support tractor modules 401, 402, 403.

The lift unit 710 has a left-right symmetrical configuration with frame 715, 717 panels on the left and right sides, a rack 721 affixed to the one frame 715, and another rack 723 affixed to the other frame 717. The three tractor modules 401, 402, 403 (tractors) are disposed to the lift unit 710 in a vertical stack between the frames 715, 717. The tractor modules 401, 402, 403 are removably installed to the frames 715, 717. The tractor modules 401, 402, 403 are held stationary by being fit into channels formed in the frames 715, 717, for example. The lift unit 710 also has a divider 712 that covers the top and back of the rear tractor unit 17.

The lift mechanism 700 has a pair of left and right stationary panels 711, 713 that are affixed to the outside case 701 and printer unit 10, a connecting rod 705 spanning between the stationary panels 711, 713, and pinion gears 704, 706 attached to the ends of the connecting rod 705. A lever 703 is attached to pinion gear 704.

The stationary panels 711, 713 are flat members disposed to opposite sides of the paper feed entrance 18. The connecting rod 705 passes through the stationary panels 711, 713, and is supported freely rotatably on the stationary panels 711, 713. When the lever 703 is moved in the direction of arrow A in FIG. 16, the pinion gear 704 moves and rotates in conjunction with the lever 703. Rotation of the pinion gear 704 is transferred through the connecting rod 705 to the other pinion gear 706. As a result, the pinion gears 704, 706 rotate together.

FIG. 19 is an enlarged oblique view showing the configuration of the tractor unit 7, and more particularly an enlarged view of the pinion gear 704 and adjacent area. Teeth 704 a are formed on the outside surface of the pinion gear 704. The teeth 704 a mesh with the teeth 721 a formed on the surface of the rack 721. The frames 715, 717 of the lift unit 710 are attached to the stationary panels 711, 713 of the lift mechanism 700 so that they can move up and down. When the lever 703 is operated in the direction of arrow A in the figure and the pinion gear 704 turns, drive power is therefore transferred from the pinion gear 704 to the rack 721. As a result, the lift unit 710 moves vertically in the direction of arrow B together with the rack 721.

As shown in FIG. 18, teeth 706 a are formed on the outside surface of the pinion gear 706 linked to pinion gear 704. Teeth 723 a (FIG. 21) are formed on the surface of the rack 723 opposite the pinion gear 706 similarly to rack 721. The teeth 706 a of the pinion gear 706 mesh with the teeth 723 a of the rack 723. As a result, when the lever 703 is operated, drive power is transferred from the pinion gear 706 to the rack 723, causing the lift unit 710 to move vertically in the direction of arrow B. Drive power is thus transferred to the lift unit 710 through the racks 721, 723 disposed at opposite sides of the lift unit 710 width. The lift unit 710 thus moves smoothly without becoming unbalanced and tilting to the left or right side.

The lift mechanism 700 and racks 721, 723 thus together render a moving mechanism.

FIG. 20 is an oblique view of the tractor module 401. The tractor module 401 has a rectangular frame 141 (protruding part), and a pair of left and right tractors 120, 130 that convey the continuous paper 2 inside the frame 141. The frame 141 is a rectangular member that encloses the sides and back of the tractor module 401, and is open at the front of the tractor module 401. Like tractor module 401, tractor modules 402 and 403 also have a pair of tractors 120, 130 inside a rectangular frame 142, 143 (protruding part), respectively. The frames 142, 143 enclose the sides and back of the tractor module 402, 403. The pair of tractors 120, 130 are disposed at the front end of the frame 141. Like frame 141, frames 142, 143 also have the pair of tractors 120, 130 disposed to the front end.

Tractor 120 and tractor 130 are symmetrical left and right. Tractor module 401 has a tractor drive shaft 115 and follower shaft 116 that pass through the tractors 120, 130.

As indicated by arrow F in FIG. 20, the tractor module 401 lifts and conveys the continuous paper 2 from a stack stored below the tractor module 401 toward the paper feed entrance 18 of the printer unit 10 as indicated by arrow G in the figure. The continuous paper 2 then rides onto the back of the frame 141 and is held by the tractors 120, 130. As a result, the corner 141 a of the top back end of the frame 141 contacts the continuous paper 2 and functions as a guide that guides the continuous paper 2.

Like tractor module 401, tractor modules 402, 403 also lift the continuous paper 2 from below the tractor modules 402, 403. The continuous paper 2 then passes from the back end of the frame 142, 143 over the top of the frame 142, 143. As a result, the corner 142 a, 143 a of the top back end of the frame 142, 143 functions as a guide for the continuous paper 2.

A gear 119 protrudes from the front of the frame 141. As a result, another gear meshes with the gear 119 from the front of the tractor module 401, and power for driving the gear 119 can be transferred to the gear 119. Tractor modules 402, 403 are constructed identically to tractor module 401. Drive power transferred to the gear 119 causes the drive sprocket and tractor drive shaft 115 to turn, and the tractors 120, 130 convey the continuous paper 2. The plural tractor modules 401, 402, 403 of the tractor unit 7 operate exclusively of each other. By operating the lever 703 to raise or lower the lift unit 710, drive power from the paper feed motor 59 is transferred to the gear 119 of only one tractor module of the tractor unit 7 at a time, and the selected tractor module conveys the continuous paper 2.

FIG. 21 is an oblique view showing the main parts in the configuration of the tractor unit 7. Because the internal configuration of the tractor unit 7 is shown in FIG. 21, the outside case 701 is not shown.

As described above, the tractor unit 7 has three tractor modules 401, 402, 403. The tractor unit 7 also has a lift unit 710 that moves up and down as indicated by arrow B, and a lift mechanism 700 that causes the lift unit 710 to move vertically. The lift unit 710 supports the tractor modules 401, 402, 403 in a stack by means of the two frames 715, 717.

The lift mechanism 700 also has a divider 712 that covers the top and back of the tractor 20 installed to the printer unit 10. This divider 712 is a panel that prevents the continuous paper 2 conveyed by the tractor unit 7 from contacting the rear tractor unit 17. The divider 712 is a substantially L-shaped panel member having a horizontal panel that covers the top of the rear tractor unit 17 joined to a vertical panel that covers the back of the rear tractor unit 17. The distal end of the divider 712 extends to inside the paper feed entrance 18 or just before the paper feed entrance 18.

A flat paper guide 727 is disposed at the top of the rear tractor unit 17 above the divider 712 and parallel to the divider 712. The continuous paper 2 is conveyed through the conveyance path formed between the paper guide 727 and divider 712. The distal end of the paper guide 727 also extends to inside or just before the paper feed entrance 18.

The lift mechanism 700 includes a transfer gear 731 and a tractor drive gear (transmission mechanism) 733. The transfer gear 731 is part of a gear train that transfers drive power from the paper feed motor 59 (FIG. 4) of the printer unit 10. The tractor drive gear 733 connects to the transfer gear 731 through another gear. Both gears 731, 733 are attached freely rotatably to stationary panel 713. The tractor drive gear 733 is disposed near the frame 717. The tractor drive gear 733 is positioned so that it can mesh with the gear 119 of each tractor module 401, 402, 403.

When the lift mechanism 700 moves the lift unit 710 vertically, one of the tractor modules is set to the height of the tractor drive gear 733. The lift mechanism 700 is configured so that the gear 119 of the tractor module set to the height of the tractor drive gear 733 meshes with the tractor drive gear 733. The drive power from the paper feed motor 59 is then transferred by the tractor drive gear 733 to the gear 119 meshed with the tractor drive gear 733. As a result, only the tractor module containing the gear 119 meshed with the tractor drive gear 733 conveys the continuous paper 2, and the other tractor modules are stopped. More specifically, when the lift unit 710 ascends or descends so that one of the tractor modules 101, 102, 103 is set to the specific height where it can convey the continuous paper 2, the gear 119 of that tractor module meshes with the tractor drive gear 733 and is driven.

One end of the paper guide 727 near the tractor modules 401, 402, 403 extends diagonally upward. The gap between the divider 712 and the end of the paper guide 727 tapers open as shown in FIG. 21. This end of the paper guide 727 tapers open, forming a continuous paper 2 entrance 729 for inserting the continuous paper 2 between the paper guide 727 and divider 712. The tractor unit 7 therefore enables smoothly inserting the continuous paper 2 between the paper guide 727 and divider 712.

The place where the tractors 120, 130 of tractor module 401 discharge the continuous paper 2 is discharge position 401 a. The place where the tractors 120, 130 of tractor module 402 discharge the continuous paper 2 is discharge position 402 a. The place where the tractors 120, 130 of tractor module 403 discharge the continuous paper 2 is discharge position 403 a.

When one of the tractor modules 401, 402, 403 reaches the specific height, the paper discharge position of that tractor module is opposite the entrance 729. As a result, the continuous paper 2 is discharged from the corresponding discharge position 401 a, 402 a, 403 a, and conveyed into the paper feed entrance 18.

The tractor unit 7 can thus selectively drive one of the tractor modules 401, 402, 403 by raising or lowering the lift unit 710. The tractor unit 7 can also smoothly convey the continuous paper 2 from the driven tractor module into the paper feed entrance 18. The drive power from the paper feed motor 59 is also not transferred to the tractor modules at positions separated from the specific height. For example, when tractor module 403 is at the specific height and conveys the continuous paper 2, the other tractor modules 401, 402 cannot contact the tractor drive gear 733. As a result, the drive power from the paper feed motor 59 is not transferred to tractor modules 401, 402. The continuous paper 2 will therefore not be conveyed from an unintended tractor module, and the tractor unit 7 can be assured of high reliability.

When one of the tractor modules 401, 402, 403 is driven and a different tractor module is then selected, the paper feed motor 59 is reversed to recover the continuous paper 2 to the discharge position of the tractor module being driven. The lift unit 710 is then raised or lowered to set the other tractor module to the specific height meshed with the tractor drive gear 733. When the newly selected tractor module 401, 402, 403 then conveys the continuous paper 2, the continuous paper 2 can be quickly supplied to the printer unit 10 without the continuous paper 2 colliding with the entrance 729 or missing the entrance 729.

The back ends of the frames 141, 142, 143 are at mutually different positions in the tractor unit 7. The corner 143 a of the frame 143 of the tractor module 403 at the lowest position in the stack is at the shortest horizontal distance from the paper feed entrance 18. The corner 141 a of the frame 141 of the tractor module 401 at the highest position in the stack is at the greatest horizontal distance from the paper feed entrance 18. The horizontal distance from the corner 141 a, 142 a, 143 a of the frame 141, 142, 143 to the paper feed entrance 18 is thus shortest in the frame at the bottom and increases with proximity to the top.

As a result, the continuous paper 2 lifted by tractor module 401 passes on the outside of the continuous paper 2 lifted by the tractor module 402 therebelow. There is, therefore, no contact between the continuous paper 2 conveyed by the top tractor module 401 and the continuous paper 2 raised by the tractor module 402 therebelow. The continuous paper 2 raised by tractor module 402 also travels through a position where there is no contact with the continuous paper 2 conveyed by the tractor module 403, and there is no contact between the paper 2 conveyed by different tractor modules.

As described above, the printer 100 according to the fifth embodiment of the invention has a plurality of tractor modules 401, 402, 403 that convey continuous paper 2 to the printer unit 10, and a lift mechanism 700 for switching between the plural tractor modules 401, 402, 403. The plural tractor modules 401, 402, 403 are disposed in a stack of plural vertical stages, and are configured so that there is no contact between continuous paper 2 conveyed by a tractor module located above another tractor module and the continuous paper 2 conveyed by any other tractor module located therebelow. As a result, plural tractor modules 401, 402, 403 can be disposed in a vertical stack, and the tractor modules 401, 402, 403 can selectively convey continuous paper 2. Contact between the continuous paper 2 conveyed by each of the plural tractor modules 401, 402, 403 can also be avoided. A tractor unit 7 having a plurality of tractor modules 401, 402, 403 disposed in mutual proximity can therefore stably convey continuous paper 2 to the printer unit 10.

The tractor unit 7 selects the tractor module to be used from among the plural tractor modules 401, 402, 403 by using the lift mechanism 700 to raise or lower the lift unit 710 that carries the tractor modules 401, 402, 403. As a result, a configuration that enables selectively operating any one of the tractor modules and reliably stopping operation of the other tractor modules can be achieved.

Each of the tractor modules 401, 402, 403 lifts and conveys the continuous paper 2 from below, and the lift position from which a tractor module located above any other tractor module lifts the continuous paper 2 is on the side farther from the printer unit 10 than the lift position of the tractor modules located therebelow. Contact between the continuous paper 2 conveyed by each of the plural tractor modules 401, 402, 403 stacked one above the other can therefore be reliably avoided. The tractor unit 7 can therefore consistently convey continuous paper 2 to the printer unit 10.

The frames 141, 142, 143 disposed to the corresponding tractor modules 401, 402, 403 extend to the side away from the printer unit 10 and guide the continuous paper 2 lifted from below so that it does not contact the continuous paper 2 conveyed by another tractor module. As a result, the plural tractor modules 401, 402, 403 disposed one above the other can keep the continuous paper 2 conveyed by each separated. A configuration that avoids contact between the continuous paper 2 conveyed by each tractor module 401, 402, 403 can therefore be easily achieved.

The back end of the frame of the tractor module located higher in the stack of plural tractor modules 401, 402, 403 extends to a position separated further from the printer unit 10 than the back end of the frame of any tractor module located therebelow. As a result, the continuous paper 2 conveyed by each of the plural, vertically stacked tractor modules 401, 402, 403 can be separated from each other. As a result, a configuration that avoids contact between the continuous paper 2 conveyed by each of the tractor modules 401, 402, 403 can be easily achieved.

The lift mechanism 700 has pinion gears 704, 706, a connecting rod 705, and racks 721, 723 as a moving mechanism that moves the plural tractor modules 401, 402, 403 vertically, and a tractor drive gear 733 as a transmission mechanism that transfers drive power to the one tractor module 401, 402, 403 in the group of plural tractor modules 401, 402, 403 that is set to a specific height. As a result, the tractor module used to convey continuous paper 2 to the printer unit 10 can be easily selected from among the plural tractor modules 401, 402, 403. In addition, only the tractor module that is selectively set from among the plural tractor module 401, 402, 403 to the specific height conveys continuous paper 2 to the printer unit 10. A special construction is therefore not required for the part of the printer unit 10 that receives the continuous paper 2. The tractor unit 7 can therefore consistently supply the continuous paper 2 to the printer unit 10.

Embodiment 6

FIG. 22 is a section view showing main parts of the tractor unit 7 a according to a sixth embodiment of the invention. Because FIG. 22 shows the internal configuration of the tractor unit 7 a, the outside case 701 is not shown. Note that like parts in this sixth embodiment and the first or fifth embodiments described above are identified by the same reference numerals, and further description thereof is omitted or simplified.

This tractor unit 7 a has a lift unit 710 a that holds a plurality of tractor modules 171, 172, 173 (tractors) on multiple vertical levels. Similarly to the lift unit 710 of the tractor unit 7 (FIG. 21) described above, the tractor unit 7 a can move the lift unit 710 a vertically by means of the lift mechanism 700.

Tractor module 171 is disposed to the top level, tractor module 172 is located therebelow, and tractor module 173 is installed to the lowest level in the lift unit 710 a. The tractor modules 171, 172, 173 are supported by a pair of left and right frames 715, 717 similarly to the tractor modules 401, 402, 403 described above (FIG. 21).

Tractor module 171 has a rectangular frame 181 (protruding part). The back end of the frame 181, that is, the end at the rear, extends down, forming an extension 181 b. Other than the shape of the frame 181, this tractor module 171 is configured identically to tractor module 101 described above. Like tractor module 171, tractor module 172 has a rectangular frame 182 (protruding part). The back end of the frame 182, that is, the end at the rear, extends down, forming an extension 182 b. Tractor module 173 has a rectangular frame 183 (protruding part). The back end of the frame 183, that is, the end at the rear, extends down, forming an extension 183 b. Other than the shape of the frame 182, 183, tractor modules tractor module 172, 173 are configured identically to tractor modules 102, 103 described above.

The horizontal distance of the extensions 181 b, 182 b, 183 b from the printer unit 10 increases from bottom to top. More specifically, the extension 181 b at the highest position is separated the most from the printer unit 10. Extensions 182 b, 183 b are sequentially closer to the printer unit 10. As a result, the corner 181 a that is contacted by the continuous paper 2 lifted by tractor module 171 is at the greatest horizontal distance from the printer unit 10. The corner 181 a that is contacted by the continuous paper 2 lifted by tractor module 171, the corner 182 a that is contacted by the continuous paper 2 lifted by tractor module 172, and corner 183 a that is contacted by the continuous paper 2 lifted by tractor module 173, are sequentially closer to the printer unit 10.

As a result, the continuous paper 2 lifted by tractor module 171 passes on the outside of the continuous paper 2 lifted by tractor module 172. Likewise, the continuous paper 2 lifted by tractor module 172 passes a position where the paper does not contact the continuous paper 2 lifted by tractor module 173. There is, therefore, no concern about contact between the continuous paper 2 conveyed by each of the tractor modules 171, 172, 173.

As also described above, the frame 181 has an extension 181 b. As a result, the continuous paper 2 conveyed by the tractor module 171 cannot approach the frame 182 below. For example, even if a force causing the continuous paper 2 to swing towards the printer unit 10 is applied by some external force or how the continuous paper 2 is stacked, for example, the continuous paper 2 will be prevented from approaching the frame 182 below by the extension 181 b. Frame 182 likewise has an extension 182 b. As a result, even if an external force or other force causing the continuous paper 2 to swing towards the printer unit 10 is applied to the continuous paper 2, the continuous paper 2 will not approach the frame 183 below. Contact between the continuous paper 2 lifted and conveyed by the plural tractor modules 171, 172, 173 can therefore be reliably avoided. Conveyance problems in the tractor unit 7 a caused by contact between the continuous paper 2 lifted by the different tractor modules 171, 172, 173 can therefore be prevented, and continuous paper 2 can be reliably conveyed.

Embodiment 7

FIG. 23 is a section view of main parts in the tractor unit 7 b according to a seventh embodiment of the invention. Because FIG. 23 shows the internal configuration of the tractor unit 7 b, the outside case 701 is not shown. Note that like parts in this sixth embodiment and the first or fifth embodiments described above are identified by the same reference numerals, and further description thereof is omitted or simplified.

This tractor unit 7 b has a lift unit 710 b that holds a plurality of identically configured tractor modules 401 on multiple vertical levels offset at an angle to the perpendicular. The tractor unit 7 b can move the lift unit 710 b up and down along this slope by means of a lift mechanism 700 b.

The lift mechanism 700 b has pinion gears 704, 706 and two racks 765. The pinion gears 704, 706 are turned by operating a lever 703. The two racks 765 have teeth 765 a that mesh with the teeth 704 a, 706 a formed on the outside of the pinion gears 704, 706. The lift mechanism 700 b and racks 765 together form a moving mechanism. Note that the rack 765 having teeth 765 a that mesh with the teeth 704 a of pinion gear 704 is not shown in FIG. 23.

The lift unit 710 b supports three tractor modules 401 with a pair of left and right stationary panels 719 disposed similarly to the stationary panels 711, 713 described above. The tractor modules 401 are disposed in steps that move further away (to the rear) from the printer unit 10 horizontally as the height increases.

As shown in FIG. 23, the racks 765 are attached to the stationary panels 719 at an angle matching the arrangement of the plural tractor modules 401. As a result, operation of the lift mechanism 700 b causes the lift unit 710 b to ascend and descend at an angle as indicated by arrow H in the figure. The direction in which the lift unit 710 a ascends and descends matches the direction in which the three tractor modules 401 are disposed.

Of the three tractor modules 401, the gear 119 of the tractor module 401 at a specific height meshes the tractor drive gear 733. As a result, drive power from the paper feed motor 59 is transferred to the gear 119. The continuous paper 2 conveyed by the tractor module 401 at this specific height passes through the conveyance path formed by the paper guide 727 and a flat divider 735 that covers the top of the rear tractor unit 17, and is fed into the paper feed entrance 18. The lift unit 710 b ascends and descends on a slope. As a result, even if the horizontal distance of each tractor module 401 from the paper feed entrance 18 differs, the three tractor modules 401 will sequentially mesh the tractor drive gear 733 as the lift unit 710 b ascends and descends, and be able to convey the continuous paper 2. Therefore, the tractor module 401 used to convey continuous paper 2 to the paper feed entrance 18 can be selected from among the plural tractor modules 401 by operating the lever 703.

The three tractor modules 401 in this configuration are disposed so that the horizontal distance of the corner 141 a of each tractor module 401 from the printer unit 10 increases from bottom to top. As a result, the continuous paper 2 that is lifted by the top tractor module 401 passes on the outside of the continuous paper 2 that is conveyed by the tractor module 401 therebelow. As a result, there is no concern about contact between the continuous paper 2 lifted by the top tractor module 401 and the continuous paper 2 lifted by the tractor module 401 therebelow. Likewise, there is no contact between the continuous paper 2 lifted by the bottom tractor module 401 and the continuous paper 2 lifted by the tractor module 401 thereabove. Contact between the continuous paper 2 lifted by the plural tractor modules 401 can therefore be reliably avoided. The tractor unit 7 b therefore prevents conveyance problems caused by contact between the continuous paper 2, and can reliably feed continuous paper 2 to the printer unit 10.

As shown in FIG. 23, the tractor unit 7 b is configured so that there is no contact between the continuous paper 2 conveyed by each tractor module on a different level even without changing the size of the frame of each tractor module 401, for example. Limitations on the shape and size of the tractor module used in each stage can therefore be alleviated.

Note that this seventh embodiment describes a configuration that uses three tractor modules 401 with the same configuration and size, but tractor modules with different frame sizes can also be used. In this case a lower tractor module can have greater horizontal length than the tractor module thereabove. By adjusting the angle at which the tractor module is disposed on each level, contact between the continuous paper 2 conveyed by tractor modules of different sizes can be avoided if the difference in the size of the frame of each tractor module is relatively small.

The above first to seventh embodiments each describe exemplary embodiments of the invention, but the invention is not limited thereto. For example, the paper feed entrance 18 opens to the back of the printer unit 10 in printers 1, 100 described above, and exemplary configurations that supply the continuous paper 2 from the back (rear) of the printer unit 10 to the paper feed entrance 18 are described. However, the invention is not so limited. For example, the printer 1, 100 could be configured to supply the continuous paper 2 from the front of the printer unit 10 or from the bottom of the printer unit 10. In these configurations the tractor unit 5, 7, 7 a, 7 b is disposed at the front of the printer unit 10 or at the bottom at the back of the printer unit 10.

A configuration in which the printer 1, 100 has a plurality of paper feed entrances to which the continuous paper 2 is supplied, and the tractor unit 5, 7, 7 a, 7 b is disposed to one of the paper feed entrances, is also conceivable.

Further alternatively, configurations in which the printer 1, 100 records on cut sheet paper in addition to continuous paper 2 are also conceivable. In this case the printer 1 may have separate conveyance paths for the cut sheet paper and continuous paper 2.

Further alternatively, the number of tractor modules disposed in the configuration holding a plurality of tractor modules one above the other in the foregoing embodiments is not limited, and there could be two or four or more.

Configurations in which the printer 1, 100 uses a mixture of the tractor modules 101, 102, 103, 171, 172, 173, 301, 303, 305, 401, 402, 403 described above are also conceivable.

Configurations in which the rear tractor unit 17 disposed to the rear of the printer unit 10 of the printer 1, 100 is removed before the tractor modules 5, 7, 7 a, 7 b are installed are also conceivable.

The printer 1, 100 could also have a conveyance mechanism for conveying roll paper or cut sheet paper instead of the rear tractor unit 17 described above.

Further alternatively, the printer 1 could be configured without the lever 92 disposed to the selection wheel 93 as described above. In this configuration the selection wheel 93 is exposed outside the base 90, and the tractor module is changed by rotating the selection wheel 93 directly. Other aspects of the printers 1, 100 described above can also obviously be changed without departing from the scope of the accompanying claims.

The foregoing embodiments are described using an inkjet printer as an example of the recording device, but the invention is not so limited and can obviously be applied to other types of printers, including dot impact printers, thermal printers that record images on thermal paper using a thermal head, and dye sublimation printers, and other types of electronic devices that include a printer as a component thereof.

The foregoing embodiments describe configurations that can accommodate a plurality of tractor modules 101, 102, 103, 171, 172, 173, 301, 303, 305, 401, 402, 403 in close proximity to each other. In close proximity as used herein is not limited to configurations in which no parts of the tractor modules 101, 102, 103, 171, 172, 173, 301, 303, 305, 401, 402, 403 touch, and includes configurations in which the frames of adjacent tractor modules, for example, may touch each other.

The invention being thus described, it will be obvious that it may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the following claims. 

What is claimed is:
 1. A tractor that conveys a recording medium, and comprises: a gear that receives drive power from the recording device side; a conveyance unit that conveys the recording medium in a specific direction by rotation of the gear; and a frame that guides the recording medium supplied from an external source to the conveyance unit.
 2. The tractor described in claim 1, wherein: the frame has a supply-side guide that passes the recording medium.
 3. The tractor described in claim 1 or 2, wherein: the frame has a discharge-side guide that passes the recording medium conveyed by the conveyance unit.
 4. The tractor described in claim 3, wherein: the discharge-side guide has an opening on the discharge side from which the recording medium is discharged, and an opening on the conveyance unit side, and the width of the opening on the conveyance unit side is narrower than the width of the opening on the discharge side.
 5. A tractor unit comprising: a plurality of tractors, each of which conveys a recording medium, and has a gear that receives drive power from the recording device side, a conveyance unit that conveys the recording medium in a specific direction by rotation of the gear, and a frame that guides the recording medium supplied from an external source to the conveyance unit; and a base that removably holds the plural tractors, and has at least one transfer gear that receives and transfers drive power from a power transfer unit disposed on the recording device side to the gears of the plural tractors.
 6. The tractor unit described in claim 5, wherein: the plural tractors are disposed in plural stages vertically, and configured so that the recording medium conveyed by the tractor located above another tractor does not contact the recording medium conveyed by the lower tractor; and the tractor unit has a selection mechanism that changes the tractor that receives drive power from the transfer gear.
 7. The tractor unit described in claim 6, wherein: the selection mechanism has a moving mechanism that moves the tractors held in plural stages vertically; and the transfer gear transfers drive power to the tractor at a specific height in the group of plural tractors.
 8. The tractor unit described in claim 6, wherein: each tractor lifts and conveys the recording medium from below; and the lifting position at which a tractor located above another tractor lifts the recording medium is on the side separated more from the recording device than the lifting position of the tractor located therebelow.
 9. The tractor unit described in claim 8, wherein: the frame is disposed to the tractor extending to the side away from the recording device, and guides the recording medium lifted from below so that the recording medium does not contact the recording medium conveyed by another tractor.
 10. The tractor unit described in claim 9, wherein: the frame of the tractor located higher in the group of plural tractors extends to a position separated farther from the recording device than the frame of the tractors located therebelow.
 11. The tractor unit described in claim 9, wherein: the plural tractors are positioned along a slope to the vertical so that the distance from the recording device increases as the height of the position increases.
 12. A recording device comprising: a tractor unit having a plurality of tractors that convey recording media, and a base that removably holds the plural tractors, each tractor of the tractor unit having a gear that receives drive power from the recording device side, a conveyance unit that conveys the recording medium in a specific direction by rotation of the gear, and a frame that guides the recording medium supplied from an external source to the conveyance unit, and the base of the tractor unit having at least one transfer gear that receives and transfers drive power from a power transfer unit disposed on the recording device side to the gears of the plural tractors.
 13. The recording device described in claim 12, wherein: the plural tractors are disposed in plural stages vertically, and configured so that the recording medium conveyed by the tractor located above another tractor does not contact the recording medium conveyed by the lower tractor; and the tractor unit has a selection mechanism that changes the tractor that receives drive power from the transfer gear. 